The death toll from twin bombings in the Afghan capital Kabul has increased to 38, with civilians and military personnel among those killed.

Mohibullah Zeer, an official in the Public Health Ministry, said another 72 people were injured in the attack, which took place near government and legislative offices.

Interior Ministry spokesman Sediq Sediqqi said a suicide bomber struck first, followed by a car bomb, and four police officers were among those killed.

The Taliban, which is waging a 15-year war against the Afghan government, said it was behind the attack.

Ghulam Faroq Naziri, a politician from the western Herat province, said another MP from the same province, Rahima Jami, was wounded.

It appeared to be the deadliest attack in Kabul since July, when two suicide bombers struck a demonstration held by Hazaras, a Shiite Muslim ethnic group, killing 80 people. That attack was claimed by a local affiliate of the Islamic State group.

The fighting in Afghanistan tends to taper off during the winter months, when mountain supply routes used by the insurgents are impassable.

Earlier in the day, a suicide bomber on foot struck in the southern Helmand province, killing at least seven people, said Gen Agha Noor Kemtoz, the provincial police chief.

The target of the attack was a guest house used by a provincial intelligence official in Lashkar Gah, the provincial capital, he said.

Those killed include civilian and military personnel, and six others were wounded in the attack, Gen Kemtoz said.

A car full of explosives was found nearby.

The Taliban also claimed that attack.

In the southern Kandahar province, two explosions inside the governor's compound killed five people and wounded another 12, including Gov Homayun Azizi, his spokesman said.

The spokesman, Samim Khpolwak, who was lightly wounded, said it was not yet clear what caused the blasts.

An attack within the heavily guarded compound would indicate a major security breach.